2009–15 Oklahoma earthquake swarms

Oklahoma area earthquake swarms

Map of earthquakes greater than 3.0 magnitude

Seismicity map for Oklahoma and nearby areas – Dark blue circles indicate earthquakes from pre-2009 while circles of other colors indicate earthquakes since 2009.
Date 2009–present
Duration About six years
Type Intraplate earthquakes
Areas affected Central and North-Central Oklahoma
South-Central Kansas
Dallas–Fort Worth metroplex
Total damage Unknown
Max. intensity VIII - Severe (November 5, 2011 Oklahoma earthquake)
Casualties Minor injuries associated with November 5, 2011 Oklahoma earthquake
Greatest magnitude 5.6 (Mw) (November 5, 2011 Oklahoma earthquake near Sparks/Prague area)
Mean depth 5.43 km (3.37 mi) in 2014[1]
Total events

>3,600 in OK since January 1, 2009 (USGS)[2]

>8,400 in OK since January 2, 2008 (OGS)[3][lower-alpha 1]

>200 in KS since January 1, 2013 (USGS)[4]

>140 in TX since January 1, 2009 (USGS)[5]

Beginning in 2009, the frequency of earthquakes in the U.S. State of Oklahoma rapidly increased from an average of approximately two 3.0+ Mw earthquakes per year to hundreds in 2014 and 2015. Thousands of earthquakes have occurred in Oklahoma and surrounding areas in southern Kansas and North Texas since 2009.[6] Events continued to increase in frequency; one of the most significant earthquakes of this swarm was a 5.6 magnitude earthquake east of the Oklahoma City area which was the strongest earthquake in the history of Oklahoma.[7] Thousands of earthquakes have already occurred in association with the swarms. Multiple seismologists advised local residents of an even greater risk of earthquakes in 2014 when the amount of earthquakes increased to a dangerously high level. To date, no less than six individual earthquake sequences in Oklahoma have been identified and named by the Oklahoma Geological Survey.[8] Other swarms exist in south-central Kansas and North Texas.

Since 2009, earthquakes in Oklahoma, especially in central and north-central areas of the state, have increased in frequency by an extreme amount. The annual total for earthquakes greater than or equal to magnitude 3.0 on the moment magnitude scale has rapidly increased in number. The annual average for 1970 to 1999 was approximately 1.6, and there was little change in this trend from 2000 to 2008. However, starting in 2009, this number rapidly increased each year, with a brief decrease in 2012. According to data from the United States Geological Survey, there have been 1,115 earthquakes of greater than or equal to moment magnitude 3.0 associated with the earthquake swarms from the beginning of 2009 through April 15, 2015.[9] Through 4:00 p.m. CDT (2100 UTC) April 25, 2015, according to the United States Geological Survey, there have been no less than 33 earthquakes of greater than or equal to moment magnitude 4.0.[10]

Background

The first earthquake known to have occurred within the boundaries of Oklahoma occurred in September 1918 when a series of shocks were felt in El Reno, Oklahoma, the strongest of which was an estimated intensity V on September 10. On Sevember 27, 1929, another tremor of intensity VI was centered in the same area and was felt in central and western Oklahoma; minor damage occurred in nearby areas and a chimney fell. The total felt area was across an area of approximately 20,000 km2 (7,700 sq mi).[11]

A magnitude 5.5 earthquake occurred near El Reno on April 9, 1952 at 10:29 a.m. CST (16:29 UTC), and at the time, it was the strongest earthquake ever recorded in Oklahoma. Most of Oklahoma was affected, as were parts of Arkansas, Iowa, Kansas, Missouri, Nebraska, and Texas. Damage was not extensive, but local residents were alarmed, and several thousands of dollars in damages occurred. Chimneys were toppled, walls were cracked, windows were broken, and bricks were loosened from buildings. In Oklahoma City, a crack measuring 15 meters (49 ft) was found in the State Capitol following the earthquake. The earthquake, which occurred along the Nemaha Fault, had a maximum intensity of VII near the epicenter.[11][12]

Scattered earthquakes occurred in Oklahoma between 1952 and 1969 with intensities as high as VII.[11] Between 1978 and 2008, the average long-term rate of earthquakes was approximately two earthquakes of magnitude 3.0 or greater per year.[6] However, in 2009, this number jumped to 20 with the beginning of several swarms of earthquakes in Oklahoma.[13]

Earthquakes

2011–12

Damage from the magnitude 5.6 earthquake on November 5, 2011, the largest earthquake on record in the state

A rise in seismicity in Oklahoma was observed in 2011. Early on the morning of November 5, 2011, an earthquake with a magnitude of 4.8 struck an area east of Oklahoma City roughly centered between Sparks and Prague. At the time, it was the strongest earthquake associated with the rise in Oklahoma's seismicity. Less than a day later at 10:53 p.m., a 5.6 Mw earthquake occurred near the location of the preceding 4.8 magnitude earthquake, becoming the strongest earthquake observed with any of the swarms as well as the strongest earthquake in the history of Oklahoma. This also resulted in the reclassification of the magnitude 4.8 earthquake as a foreshock and the 5.6 magnitude earthquake as the mainshock.[14] The earthquake received over 66,000 "Did You Feel It?" responses nationwide sent to the United States Geological Survey.[15] It was believed that the earthquake had occurred along the Wilzetta Fault, also known as the Seminole Uplift. Following this earthquake, several portable seismograph stations were established by the USGS, OGS, and University of Oklahoma School of Geology and Geophysics to aid with detection of future earthquakes in the area.[7] The 5.6 Mw mainshock was followed by a magnitude 4.8 aftershock slightly under two days later, and numerous other aftershocks occurred in the following months.[16][17] Through the end of 2011, 64 earthquakes were recorded, nearly double the number recorded for 2010.[13]

2012 saw a decrease in seismic activity in Oklahoma when compared to 2011, with a recorded annual total of 35 earthquakes magnitude 3.0 or greater, 29 less than recorded in the previous year.[13]

2013–14

On December 7, 2013, an earthquake occurred within the city limits of Oklahoma City in any area south of Lake Arcadia with a magnitude of 4.5 Mw. This was the strongest earthquake to occur in Oklahoma since the November 5, 2011 earthquake near the Prague–Sparks area east of Oklahoma City.[18] For 2013, an estimated 109 earthquakes occurred according to the Oklahoma Geological Survey, a number substantially higher than in any previous year going back to 1978.[13]

The 2014 total of 3.0+ magnitude earthquakes by May 2 was higher than the entire yearly total for 2013, at over 140 earthquakes. The number of earthquakes in Oklahoma increased by about 50% from October 2013 to May 2, 2014, prompting the United States Geological Survey to issue an uncommon "Earthquake Advisory" for Central Oklahoma warning of the elevated possibility of damaging, 5.5+ magnitude earthquakes. This was the first advisory in the United States ever issued east of the Rocky Mountains and remains effective.[6]

Seismic hazard map for Oklahoma for 2014 – this hazard map does not account for the recent earthquakes and potentially induced seismicity

On July 17, 2014, the United States Geological Survey released an updated map identifying seismic hazard for the continental United States.[19] However, the earthquakes occurring in much of Oklahoma were not included in the creation of the map, for it is believed by the USGS that some degree of the earthquakes may have been induced by wastewater injection, and the map is meant to represent natural seismicity alone due to the unpredictable nature of earthquakes created by human industrial activities. Austin Holland of the OGS voiced concerns about the removal of the earthquakes in the map's creation, and he said "By removing them, we are underestimating the potential of serious seismic hazard in Oklahoma." William Ellsworth of the USGS responded by mentioning that the USGS was working on a new hazard model; "Everyone here thinks quakes, regardless of origin, need to be accounted for in our hazard model," he said.[20]

In 2013, seismologist Katie Keranen, a professor at the University of Oklahoma at the time, published a peer-reviewed paper about the relationship of disposal wells and the November 5, 2011 Prague earthquake discussing a "compelling link between the zone of injection and the seismicity." However, the Oklahoma Geological Survey rejected these findings. A brief period prior to the publication of Keranen's paper, the OGS had released a statement saying "The interpretation that best fits current data is that the Prague earthquake sequence was the result of natural causes."[21]

The swarms, while initially located primarily further south, traveled northward from Central Oklahoma into Logan County in early 2014. Additional earthquake swarms initiated in north-central Oklahoma, including areas near Medford, Oklahoma. The latter swarms crossed into southern Kansas in 2013. Many earthquakes have also occurred in the southernmost part of Kansas since they began, with the most significant being a magnitude 4.9 earthquake on November 12, 2014, the strongest earthquake produced by the swarms since a magnitude 4.5 earthquake struck in Northeast Oklahoma City on December 7, 2013 almost a year earlier.[18][22]

2015

Graph of 3.0+ magnitude earthquakes on the moment magnitude scale known to have occurred annually in Oklahoma up through September 24, 2014 (incorporates OGS data) – a drastic increase can be seen starting in about 2009.

By the end of 2014, 567 earthquakes of at least magnitude 3.0 were recorded in Oklahoma, more than the number of 3.0+ magnitude earthquakes from the previous 30 years combined.[23] This was a fivefold increase from the previous year; in 2014, there were over twice as many earthquakes recorded in Oklahoma as compared to California, making Oklahoma the most seismically active state in the contiguous United States by a substantial margin. In a review by EnergyWire, earthquakes of greater than or equal to magnitude 3.0 were examined, and it was found that seismic activity in Oklahoma had been spreading northward into Kansas which experienced a major jump in earthquakes from 2013 to 2014.[24]

Animation of all earthquakes in Oklahoma from January 2, 2008 to April 13, 2015

As in southern Kansas, earthquakes increased in frequency in North Texas with over 130 earthquakes occurring in the area from 2009 to early 2015.[25] It was later announced that, for the first time, the United States Geological Survey would include earthquakes believed to have connections to industrial activities in its National Seismic Hazard Map which sets standards for construction and insurance rates.[26] According USGS National Seismic Hazard Project head Mark Petersen, an updated version of the map will become available before the end of 2015. This marks a deviation from the past, with the USGS updating the National Seismic Hazard Map annually instead of every six years. Peterson also said, "It may even be more frequent than that."[27]

In 2014, the United States Geological Survey updated its National Seismic Hazard Map; however, potentially induced earthquakes were intentionally not considered in this analysis as geologists were not certain as to how to incorporate non-tectonic earthquakes. Several months later in April 2015, a comprehensive assessment was released analyzing the link between the increase in seismic activity in the Central United States and oil and gas operations. Seventeen induced seismicity zones for earthquakes over the past 50 years were delineated in this assessment, including one region encompassing northern Oklahoma and parts of southern Kansas, a second region covering central Oklahoma down to the Oklahoma–Texas border, and a third region encompassing the Dallas–Forth Worth area of Texas.[28][29]

Zones of suspected induced seismicity in the Oklahoma area

On April 21, 2015, the Oklahoma Geological Survey abandoned its skepticism of the possible link of the earthquakes to industrial activities and said in official statement that it "considers it very likely that the majority of recent earthquakes, particularly those in central and north-central Oklahoma, are triggered by the injection of produced water in disposal wells." In 2013, the seismicity rate was "70 times greater than the background seismicity rate observed in Oklahoma prior to 2008", potentially although unlikely explainable by natural variations in seismicity, but the seismicity rate by the time of statement was "about 600 times greater than the background seismicity rate" and was "very unlikely the result of a natural process."[30][31][32]

Governmental response

In September 2014, in response to the swarms of earthquakes, Oklahoma Governor Mary Fallin announced the creation of a "Coordinating Council on Seismic Activity" to help promote further understanding of the increase in seismicity. Fallin added, "We believe that by linking scientists and energy experts, we can develop sound regulatory practices and policies in our state while also alleviating any questions our citizens might have." The council, led by Michael Teague, is expected to include input from multiple areas, including "the Oklahoma Geologic Survey, the Oklahoma Corporation Commission, the Oklahoma Energy Resources Board, the University of Oklahoma, Oklahoma State University, the Oklahoma Independent Petroleum Association, the Oklahoma Oil and Gas Association, and various state legislators".[33] However, some criticized the council, saying it included too many representatives from the oil and gas industry; additional critics pointed out the fact that Michael Teague was the Oklahoma Secretary of Energy. Teague replied by saying that he was also concerned with environment, and he followed by adding, "We are talking to environmental groups and industry folks and academic folks and state agencies and how do you bring them all together?"[34]

In light of the greatly increased earthquake activity, about 15% of Oklahomans had purchased earthquake insurance by early 2015 according to Oklahoma Insurance Commissioner John D. Doak.[35]

Following earthquake activity in Alfalfa County, Oklahoma near the Kansas–Oklahoma border in late-January 2015, the Oklahoma Corporation Commission ordered SandRidge Energy to shut down an injection well it was operating. This was the second wastewater injection well directed to "shut in" or halt operations by the agency since a new monitoring system was established in 2013. According to Matt Skinner, a spokesman from the commission, the directive was issued on February 3 in response to a magnitude 4.1 earthquake recorded in the area four days earlier. According to Skinner, "They were operating under a 'yellow light' permit with language that said shut in if there's any seismic activity."[36]

After EnergyWire obtained Oklahoma Geological Survey email correspondence through an Oklahoma Open Records Act request in 2015, it was found that after the OGS acknowledged a link between oil and gas operations and the ongoing earthquakes in the latter part of 2013, state seismologist Austin Holland was called into a meeting with University of Oklahoma President David L. Boren and oil executives. Holland had previously spoken with a senior official of the United States Geological Survey discussing the connection between a swarm of earthquakes near and east of Oklahoma City. Holland wrote to USGS science advisor Bill Leith in 2013 "Since early 2010 we have recognized the potential for the Jones earthquake swarm to be due to the Hunton dewatering," but he followed by saying "But until we can demonstrate that scientifically or not we were not going to discuss that publicly." In October 2013, a joint statement between the OGS and the USGS announced that "activities such as wastewater disposal" may be a "contributing factor to the increase in earthquakes." Holland was requested a week later to come to Oklahoma Corporation Commission headquarters by then-Commissioner Patrice Douglas for a meeting. Also sent for was then-president of exploration at Continental Resources, Jack Stark. As Holland recounted in a later email, Stark and Douglas were "concerned" by the joint statement.[21] This precedes the Oklahoma Geological Survey's April 2015 change in position where the agency acknowledged that the earthquakes were "very unlikely the result of a natural process."[30]

In April 2015, after the Oklahoma Geological Survey acknowledged that the tremendous increase in the frequency of earthquake occurrence is likely due to the injection of produced water in disposal wells,[30] the State of Oklahoma launched a website providing information about earthquakes in the state, including an interactive map where both earthquakes and disposal wells can be plotted.[31][32]

See also

Notes

  1. ↑ Earthquakes included in this total have a minimum magnitude of 2.0 and are complete above a magnitude of 3.0. The total from the United States Geological Survey is significantly lower than that from the Oklahoma Geological Survey as the USGS does not report events as small as the OGS; information from the USGS is still included as its information is updated more frequently.

References

  1. ↑ Darold, Amberlee P.; Holland, Austin A.; Morris, Jennifer K.; Gibson, Amie R. (February 19, 2015). Oklahoma Earthquake Summary Report 2014 (PDF). Oklahoma Geological Survey (Report) (Norman, Oklahoma: University of Oklahoma). Archived from the original on March 16, 2015. Retrieved March 15, 2015.
  2. ↑ "USGS Map of Earthquakes (Oklahoma: 2009-01-01–2015-04-15)". Earthquake Hazards Program. United States Geological Survey. April 15, 2015. Retrieved April 15, 2015.
  3. ↑ "Animation of Oklahoma Seismicity: January 2, 2008 - April 14, 2015". Earthquake Hazards Program. United States Geological Survey. April 14, 2015. Retrieved April 15, 2015.
  4. ↑ "USGS Map of Earthquakes (Kansas: 2009-01-01–2015-04-15)". Earthquake Hazards Program. United States Geological Survey. April 15, 2015. Retrieved April 15, 2015.
  5. ↑ "USGS Map of Earthquakes (North Texas: 2009-01-01–2015-04-15)". Earthquake Hazards Program. United States Geological Survey. April 15, 2015. Retrieved April 15, 2015.
  6. ↑ 6.0 6.1 6.2 "Record Number of Oklahoma Tremors Raises Possibility of Damaging Earthquakes". United States Geological Survey, Oklahoma Geological Survey. May 2, 2014. Retrieved July 2, 2014.
  7. ↑ 7.0 7.1 "Magnitude 5.6 - Oklahoma". Earthquake Hazards Program. United States Geological Survey. November 6, 2011. Retrieved July 2, 2014.
  8. ↑ "Recent Earthquakes: Town Hall Meeting, June 26, 2014" (PDF). Oklahoma Geological Survey. University of Oklahoma. June 26, 2014. Retrieved July 13, 2014.
  9. ↑ "USGS Map of 3.0+ Magnitude Earthquakes (Oklahoma: 2009-01-01–2015-04-15)". Earthquake Hazards Program. United States Geological Survey. April 15, 2015. Retrieved April 15, 2015.
  10. ↑ "USGS Map of 4.0+ Magnitude Earthquakes (Oklahoma: 2009-01-01–2015-04-25)". Earthquake Hazards Program. United States Geological Survey. April 25, 2015. Retrieved April 25, 2015.
  11. ↑ 11.0 11.1 11.2 "Oklahoma Earthquake History". United States Geological Survey. n.d. Retrieved April 18, 2015.
  12. ↑ "Historic Earthquakes — El Reno, Oklahoma — 1952 04 09 16:29:28.4 UTC". United States Geological Survey. n.d. Retrieved April 18, 2015.
  13. ↑ 13.0 13.1 13.2 13.3 "Earthquakes in Oklahoma of M3+" (PNG). Earthquake Hazards Program. United States Geological Survey. September 24, 2014. Retrieved March 17, 2015.
  14. ↑ "M4.8 - Oklahoma". Earthquake Hazards Program. United States Geological Survey. November 5, 2011. Retrieved March 18, 2015.
  15. ↑ "M5.6 - Oklahoma (BETA)". Earthquake Hazards Program. United States Geological Survey. November 6, 2011. Retrieved July 4, 2014.
  16. ↑ "M4.8 - Oklahoma". Earthquake Hazards Program. United States Geological Survey. November 7, 2011. Retrieved April 9, 2015.
  17. ↑ "Nov. 6, 2011 M5.6 Oklahoma Earthquake Foreshocks and Aftershocks". Earthquake Hazards Program. United States Geological Survey. July 31, 2012. Retrieved March 18, 2015.
  18. ↑ 18.0 18.1 "M4.5 - 9km ESE of Edmond, Oklahoma". Earthquake Hazards Program. United States Geological Survey. December 7, 2013. Retrieved January 27, 2015.
  19. ↑ Robertson, Jessica; Petersen, Mark (July 17, 2014). "New Insight on the Nation’s Earthquake Hazards". Earthquake Hazards Program (United States Geological Survey). Retrieved August 11, 2014.
  20. ↑ Eaton, Joe (July 31, 2014). "Oklahoma Grapples With Earthquake Spike—And Evidence of Industry's Role". National Geographic Daily News (National Geographic Society). Retrieved August 11, 2014.
  21. ↑ 21.0 21.1 Soraghan, Mike (March 5, 2015). "Okla. agency linked quakes to oil in 2010, but kept mum amid industry pressure". EnergyWire (Environment & Energy Publishing, LLC). Retrieved March 9, 2015.
  22. ↑ "M4.9 - 13km S of Conway Springs, Kansas". United States Geological Survey. November 12, 2014. Retrieved February 4, 2015.
  23. ↑ Branstetter, Ziva (January 27, 2015). "Prague earthquake suit before Supreme Court could set precedent". Tulsa World. Retrieved February 9, 2015.
  24. ↑ Soraghan, Mike (January 5, 2015). "Earthquakes: Shaken more than 560 times, Okla. is top state for quakes in 2014". EnergyWire (Environment & Energy Publishing, LLC). Retrieved February 4, 2015.
  25. ↑ Kuchment, Anna; Loftis, Randy Lee; Osborne, James; Selk, Avi (January 11, 2015). "What’s at fault? Scientists seek cause of Irving earthquakes". The Dallas Morning News. Retrieved February 3, 2015.
  26. ↑ Oskin, Becky (February 12, 2015). "Hidden Faults Explain Earthquakes in Fracking Zones". LiveScience (Purch, Inc.). Retrieved February 21, 2015.
  27. ↑ Kuchment, Anna (January 31, 2015). "USGS likely to upgrade North Texas’ quake risk level". The Dallas Morning News. Retrieved February 7, 2015.
  28. ↑ Peterson, Mark D.; Mueller, Charles S.; Moschetti, Morgan P.; Hoover, Susan M.; Rubinstein, Justin L.; Llenos, Andrea L.; Michael, Andrew J.; Ellsworth, William L.; McGarr, Arthur F.; Holland, Austin A.; Anderson, John G. (April 23, 2015). Incorporating Induced Seismicity in the 2014 United States National Seismic Hazard Model—Results of 2014 Workshop and Sensitivity Studies (USGS Open-File Report 2015–1070) (PDF) (Report). United States Geological Survey. doi:10.3133/ofr20151070. ISSN 2331-1258. OCLC 38116130. Retrieved April 23, 2015.
  29. ↑ Pérez-Peña, Richard (April 23, 2015). "U.S. Maps Pinpoint Earthquakes Linked to Quest for Oil and Gas". The New York Times. Retrieved April 24, 2015.
  30. ↑ 30.0 30.1 30.2 Andrews, Richard D.; Holland, Austin A. (April 21, 2015). Statement on Oklahoma Seismicity (PDF). Oklahoma Geoogical Survey (Report) (University of Oklahoma). Retrieved April 23, 2015.
  31. ↑ 31.0 31.1 Wines, Michael (April 21, 2015). "Oklahoma Recognizes Role of Drilling in Earthquakes". The New York Times. Retrieved April 23, 2015.
  32. ↑ 32.0 32.1 "Earthquakes in Oklahoma". Office of the Oklahoma Secretary of Energy and Environment. Oklahoma City, Oklahoma: Government of Oklahoma. April 21, 2015. Retrieved April 23, 2015.
  33. ↑ Wilmoth, Adam (September 4, 2014). "Oklahoma Gov. Mary Fallin creates seismic activity council". The Oklahoman (NewsOK.com). Retrieved September 11, 2014.
  34. ↑ Stewart, Sarah (September 9, 2014). "Council to study Oklahoma earthquakes criticized for members’ professions". KFOR-TV (KFOR.com). Retrieved October 1, 2014.
  35. ↑ Wertz, Joe (January 14, 2015). "Oklahoma Earthquake Rate is High, But Holding Steady". StateImpact Oklahoma (Oklahoma Public Media Exchange). Retrieved February 4, 2015.
  36. ↑ Branstetter, Ziva (February 4, 2015). "State orders injection well shut down after northwestern Oklahoma earthquake". Tulsa World. Retrieved February 7, 2015.

External links

Wikimedia Commons has media related to Earthquakes in Oklahoma.